A lack of information from family doctors, lengthy waits and confusion were the major problems in the first week of the change to a new provider of community laboratory testing in Auckland.
Auckland district health boards have been briefed about early problems, which they say have since been largely overcome.
The boards began switching from Diagnostic Medlab to Lab Tests three weeks ago.
In a report on the first week, they have been told that test request forms with no doctor details were a problem.
Many forms had a code only, and the boards were told Diagnostic Medlab refused requests for a copy of the codes.
Officials say that's been resolved, along with waits of up to two hours for some patients.